From patchwork Thu Sep 1 13:14:36 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Leizhen (ThunderTown)" X-Patchwork-Id: 12962547 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C6CE0C54EE9 for ; Thu, 1 Sep 2022 13:19:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232771AbiIANTF (ORCPT ); Thu, 1 Sep 2022 09:19:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40844 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234293AbiIANSo (ORCPT ); Thu, 1 Sep 2022 09:18:44 -0400 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 94DD7543E5; Thu, 1 Sep 2022 06:16:04 -0700 (PDT) Received: from dggpemm500023.china.huawei.com (unknown [172.30.72.56]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4MJM050cPqzkWT5; Thu, 1 Sep 2022 21:12:21 +0800 (CST) Received: from dggpemm500006.china.huawei.com (7.185.36.236) by dggpemm500023.china.huawei.com (7.185.36.83) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Thu, 1 Sep 2022 21:16:02 +0800 Received: from thunder-town.china.huawei.com (10.174.178.55) by dggpemm500006.china.huawei.com (7.185.36.236) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Thu, 1 Sep 2022 21:16:01 +0800 From: Zhen Lei To: "Paul E . McKenney" , Frederic Weisbecker , Neeraj Upadhyay , "Josh Triplett" , Steven Rostedt , Mathieu Desnoyers , Lai Jiangshan , Joel Fernandes , , CC: Zhen Lei Subject: [PATCH v6 2/2] rcu: Offload callback processing from all CPUs in the absence of rcu_nocbs= Date: Thu, 1 Sep 2022 21:14:36 +0800 Message-ID: <20220901131436.986-3-thunder.leizhen@huawei.com> X-Mailer: git-send-email 2.26.0.windows.1 In-Reply-To: <20220901131436.986-1-thunder.leizhen@huawei.com> References: <20220901131436.986-1-thunder.leizhen@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.174.178.55] X-ClientProxiedBy: dggems702-chm.china.huawei.com (10.3.19.179) To dggpemm500006.china.huawei.com (7.185.36.236) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: rcu@vger.kernel.org Offload callback processing from all CPUs as long as there is no "rcu_nocbs=" boot parameter. This also means: whether CONFIG_RCU_NOCB_CPU_DEFAULT_ALL=y takes effect does not depend on the absence of "nohz_full=". Suggested-by: Frederic Weisbecker Signed-off-by: Zhen Lei --- kernel/rcu/Kconfig | 4 ++-- kernel/rcu/tree_nocb.h | 2 +- 2 files changed, 3 insertions(+), 3 deletions(-) diff --git a/kernel/rcu/Kconfig b/kernel/rcu/Kconfig index d471d22a5e21b43..35b94f5f6767f00 100644 --- a/kernel/rcu/Kconfig +++ b/kernel/rcu/Kconfig @@ -270,8 +270,8 @@ config RCU_NOCB_CPU_DEFAULT_ALL default n help Use this option to offload callback processing from all CPUs - by default, in the absence of the rcu_nocbs or nohz_full boot - parameter. This also avoids the need to use any boot parameters + by default, in the absence of the rcu_nocbs boot parameter. + This also avoids the need to use any boot parameters to achieve the effect of offloading all CPUs on boot. Say Y here if you want offload all CPUs by default on boot. diff --git a/kernel/rcu/tree_nocb.h b/kernel/rcu/tree_nocb.h index 8b6dceeabde0b4d..cfbdd78d6c33158 100644 --- a/kernel/rcu/tree_nocb.h +++ b/kernel/rcu/tree_nocb.h @@ -1219,7 +1219,7 @@ void __init rcu_init_nohz(void) #endif #if defined(CONFIG_RCU_NOCB_CPU_DEFAULT_ALL) - if (!rcu_state.nocb_is_setup && !cpumask) + if (!rcu_state.nocb_is_setup) cpumask = cpu_possible_mask; #endif